User Interface Method for Skew Correction

1. A method for correcting skew in an image, the method comprising: receiving, by an input device, at least two distinct points on a skew-line from a user, wherein the at least two distinct points on the skew-line are immediately updated with every move of the input device by the amount specified by a current position of the input device; calculating the sine and cosine of the skew-angle, wherein the skew-angle is the angle defined by the intersection of the skew-line with respect to a reference line, and the skew-angle is calculated using the points having coordinates (x 1 , y 1 ) and (x 2 , y 2 ), the calculating of the sine and cosine using the formulas: sin ⁡ ( θ ) = ( y 2 - y 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 , ⁢ cos ⁡ ( θ ) = ( x 2 - x 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 ; ⁢ and transforming the image according to the sine and cosine of the skew-angle, wherein the transforming is updated with the movement of the input device.

2. The method according to claim 1 , wherein the two of the at least two points are endpoints.

3. The method according to claim 1 , wherein the reference line comprises a horizontal line.

4. The method according to claim 1 , further comprising cropping the image.

5. The method according to claim 1 , wherein the two points of the skew-line are received from a user through a user interface.

6. The method according to claim 1 , further comprising displaying the image after the image has been transformed.

7. A method for correcting skew in an image, the method comprising: receiving, by an input device, a first endpoint from a user; receiving a second endpoint from the user, wherein the first and second endpoints are immediately updated with every move of the input device by the amount specified by a current position of the input device; calculating the sine and cosine of the skew-angle, wherein the skew-angle is the angle between a line defined by the first and second endpoints and a reference line, and the sine and cosine are calculated using the first and second endpoints having coordinates (x 1 , y 1 ) and (x 2 , y 2 ) using the formulas: sin ⁡ ( θ ) = ( y 2 - y 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 , ⁢ cos ⁡ ( θ ) = ( x 2 - x 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 ; ⁢ and transforming the image using the sine and cosine of the skew-angle, wherein the transforming is updated with the movement of the input device.

8. The method according to claim 7 , further comprising drawing a line between the first endpoint and the second endpoint on the display.

9. A computer system comprising: a user interface comprising a pointing device and a display; a processor; and a memory, wherein the memory comprises: instructions to store an image in the memory; instructions to display the image on the display; instructions to receive a first endpoint and a second endpoint from a user through the pointing device, wherein the first and second endpoints are immediately updated with every move of the input device by the amount specified by a current position of the pointing device; instructions to calculate with the processor the sine and cosine of a skew-angle, wherein the skew-angle is the angle between a reference line and a line defined by the first endpoint and the second endpoint, and the sine and cosine are calculated using the first and second endpoints having coordinates (x 1 , y 1 ) and (x 2 , y 2 ) using the formulas: sin ⁡ ( θ ) = ( y 2 - y 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 , ⁢ cos ⁡ ( θ ) = ( x 2 - x 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 ; ⁢ and instructions to transform the image using the sine and cosine of the skew-angle, wherein the transforming is updated with the movement of the input device.

10. The computer system according to claim 9 , further comprising instructions to display a symbol representing the first endpoint and a symbol representing the second endpoint on the display.

11. The computer system according to claim 9 , further comprising instructions to draw a line defined by the first endpoint and the second endpoint on the display.

12. The computer system according to claim 11 , further comprising instructions to erase from the display the line defined by the first endpoint and the second endpoint.

13. The computer system according to claim 9 , further comprising instructions to crop the image.

14. The computer system according to claim 9 , further comprising instructions to enlarge the image.

15. A non-transitory computer program product comprising: a computer readable medium encoded with program code for controlling operation of a computer system, the program code including: program code to display an image; program code to receive a first endpoint and a second endpoint from a user through a pointing device, wherein the first and second endpoints are immediately updated with every move of the input device by the amount specified by a current position of the pointing device; program code to calculate the sine and cosine of the skew-angle, wherein the skew-angle is the angle between a reference line and a line defined by the first endpoint and the second endpoint, and the sine and cosine are calculated using the first and second endpoints having coordinates (x 1 , y 1 ) and (x 2 , y 2 ) using the formulas: sin ⁡ ( θ ) = ( y 2 - y 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 , ⁢ cos ⁡ ( θ ) = ( x 2 - x 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 ; ⁢ and program code to transform the image using the sine and cosine of the skew-angle, wherein the transforming is updated with the movement of the input device.

16. The non-transitory computer program product according to claim 15 , further comprising program code to draw a line defined by the first endpoint and the second endpoint.

17. The non-transitory computer program product according to claim 16 , further comprising erasing the line defined by the first endpoint and the second endpoint.

18. The non-transitory computer program product according to claim 15 , wherein the first endpoint and the second endpoint is received from a user through a user interface.

19. A computer system comprising: a user interface comprising: a pointing device; a scanner; and a display; a processor; and memory, wherein the memory comprises: instructions to receive an image of a document from a scanner; instructions to store the image in the memory; instructions to check the image for skew; instructions to display the image on the display; instructions to receive a first endpoint and a second endpoint from a user through the pointing device, wherein the first and second endpoints are immediately updated with every move of the input device by the amount specified by a current position of the pointing device; instructions to calculate with the processor the cosine and sine of the skew-angle, wherein the skew-angle is the angle between a horizontal line and a line defined by the first endpoint and the second endpoint, and the sine and cosine are calculated using the first and second endpoints having coordinates (x 1 , y 1 ) and (x 2 , y 2 ) using the formulas: sin ⁡ ( θ ) = ( y 2 - y 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 , ⁢ cos ⁡ ( θ ) = ( x 2 - x 1 ) ( y 2 - y 1 ) 2 + ( x 2 - x 1 ) 2 ; ⁢ and instructions to transform the image using the sine and cosine of the skew-angle, wherein the transforming is updated with the movement of the input device.

20. The method of claim 1 , further comprising: assigning a value to the sine and cosine of the skew-angle in response to the calculating; performing a check to determine if the value assigned to the cosine is a negative value; negating the value assigned to the sine and cosine of the skew-angle in response to a determination that the value assigned to the cosine is negative.